text:
Why is using opposite rudder and aileron necessary in left turn for coordination?
This question goes against everything I've read or heard with the exception of a suggestion from my CFI in my last flight lesson, so I was hoping to get some clarification:
During a left turn into our crosswind leg my instructor informed me that I shouldn't be using so much left rudder, and in fact, might even need to use some right rudder to stay coordinated due to the left turning tendencies of the plane. I could somewhat understand given that I definitely noticed a tendency for the plane to roll more when turning left than right, but still I would think the antidote for that would just be less left rudder, not opposite rudder.
This does not make sense to me. In what situations would I need to do this? I was still able to perform my turns just fine with slight right rudder on my left turns, but I would like to understand this more.
FYI - I'm flying a Piper Cherokee 140 (PA-28-140)

Adverse Yaw: What is it, and How Do You Prevent It? and Adverse Yaw, a Stick and Rudder Fundamentals (video)

First and foremost you should always be looking at the turn coordinator to see what is going on and applying rudder as necessary.
In your specific case (if we want to discuss the physics), basically what your instructor is saying is that you are using the ailerons to bank (turn) the plane and the rudder to counteract the propeller's yawing moment. The rudder is simply counteracting the Adverse Yaw: the inputs will change depending on how steeply you are banking. If opposite rudder is called for on your ball, then step on it.
Perhaps more importantly, what your instructor is actually stressing is during your crosswind, base and final turns you should really be paying attention to staying coordinated. A great deal of Stall -> Spin -> Crashes happen in the pattern as planes slow down and dirty up, thus it's extremely important in the pattern to watch your speed and your turn coordination.

You should just look at the ball and that will remove all doubt. If the ball is to the left, you use left rudder. It's that simple.
After a while, like a couple hundred hours, you will start to feel when the aircraft is coordinated naturally, but until then just look at the ball. Don't fixate on it, though. Just glance down at some point when you are making your turn.

There are already good answers, so I won't dwell on the standard advice to look at the slip indicator and do the necessary, but I'll answer to clear up a possible misunderstanding.
You do not use rudder to correct for adverse yaw when turning. You use rudder to correct for adverse yaw when rolling into the turn. When you turn left, you put the stick left to roll to the correct bank angle, and then you put the stick in the centre to maintain that bank angle throughout the turn. While the stick is on the left, you should be applying left rudder, but as the stick goes back towards the centre, so you should be reducing the left rudder. You don't keep that left rudder in for the whole turn. Later, when you roll out of the turn, you use right rudder then while your stick is on the right, and then return the rudder to the centre when you return the stick to the centre.
When you're turning across the wind direction, you'll definitely need to adjust the rudder position because the direction of the airflow against the aircraft changes. Exactly what is different in different situations (of wind direction and turn direction). Once you've completed the roll, you need to use the correct rudder for the situation. The fact you're in a left turn doesn't mean you can only use left rudder.

The other answers have good general discussions of engine- and propeller-induced left turning tendencies, but I don't think anyone's addressed the exact situation your instructor gave you that piece advice in, namely the crosswind turn in the traffic pattern.
At that particular point of the pattern, unless you've extended your upwind leg until you've reached pattern altitude and leveled off, you will still be flying at a relatively slow speed (so flight controls are less effective, including the little rudder trim tab on your vertical stabilizer), with a high engine power setting (so lots of torque and a nice, fast spiraling slipstream), and in a nose-high attitude (so p-factor comes into play in a big way).
All of these things combine to impart more left-yawing and -rolling tendencies on the aircraft than at just about any other point in the traffic pattern. Quite a few aircraft, in fact, require minimal, if any, inputs to initiate a left turn from this attitude. As you've seen yourself, you might have to add opposite rudder just to keep the aircraft coordinated while it's doing its thing.
If you're looking for more practical demonstrations of this (as well as how this differs from making turns to the right from this attitude), I recommend asking your instructor to give you a brief introduction to chandelles. They're great for demonstrating and understanding the turning tendencies imparted by the engine at different airspeeds and pitch attitudes (and a lot of fun to boot).

That's all going to be dependent on aircraft type, configuration and flight characteristics, but your instructor is right.
Rudder is necessary to correct for adverse yaw due to the drag created by the upraised aileron in a turn.  In steep turns, the outside wing is traveling faster through the air than the inside wing, generating more lift than the outside wing and causing a tendency for the airplane to continue to increase its angle of bank.  This would be counteracted by opposing aileron input, which in turn creates adverse yaw toward the outside of the turn.  Opposite rudder will be required to correct for this.  This would be particularly pronounced during flight at slower speeds where it is much more noticeable.
The total required control inputs may be composed of a number of factors, most of which are related to the propellor, such as p-factor, prop wash on the fuselage, gyroscopic precession, etc.  but yes, your instructor is right and you may see a skidding turn as a result.

I'm assuming that you are climbing at full power as you're turning left. In this position everything thrust related is essentially creating both left roll and left yaw. Left Yaw in a left bank creates a nose down tendency and may indeed un-coordinate your turn to a point whereas right rudder may be needed which is admittedly cross sticking, BUT IS IT??? Essentially the torque and particularly the P factor may be providing "too much Yaw input" all by itself and the only way to lessen it is to apply right rudder. AKA the p factor and many other "full power" attributes is already adding what is "effectively" "too much" left "rudder input" (even though it's P factor input) and in extreme cases (as is full power and turning left), especially if airspeed begins reducing too, there will be a point whereas the pilot would need right rudder in a left turn. The Ball doesn't lie, step on it!!!

I agree that this sounds counterintuitive, and my gut tells me that there is some misunderstanding here.
Torque and p-factor will have a greater effect at the lower speed in the traffic pattern.  If, in level flight, you are holding right rudder, then maybe when you're rolling left all you need is a reduction of right and not necessarily input of left in order to maintain coordination.
I have very strong doubts that what your instructor is telling you is that you should add right rudder, in the sense of increase it, as you roll left.  If anything it is a decrease of right rudder.
However, a reduction of right rudder during the roll is still right rudder in the same way that turning a car's wheels toward center, but still being in a right turn is not considered turning your car left.

just thought I would note that I believe torque causes rotation around the longitudinal axis (left wing down)and is corrected with aileron input. P-Factor causes rotation to the left around the vertical axis (yaw) and is corrected with opposite rudder as needed.


text:
Is it legal to fly in RVSM airspace with an inoperative autopilot?
FAR Part 91, Appendix G, Section 2 says:

(c) Altitude-keeping equipment: All aircraft. To approve an aircraft
  group or a nongroup aircraft, the Administrator must find that the
  aircraft meets the following requirements:
...
 (2) The aircraft must be equipped with at least one automatic altitude
  control system that controls the aircraft altitude

Note that it does not say that it must be engaged, or even operative.  Simply "equipped", and also that this is to approve an aircraft for RVSM.  From what I can find, there is no operational requirement for the autopilot to actually be working or engaged.
Assuming that my MEL allows me to defer the autopilot and still fly, can I fly in RVSM airspace?  Some people however say that if you are in RVSM airspace that the autopilot must be working and engaged.  Right or wrong?

That's pretty bald-faced rules lawyering. By that logic, anyone could throw an cardboard box with the word "autopilot" sharpied on and have "the autopilot" "equipped" and do the exact same amount of good.
Equipment has to be operable, or it's as good as not there. (Worse, actually, because it adds to the plane's mass.)

@rsegal: The regulations are written by lawyers using very specific wording for a reason.  There are minimum requirements for the autopilot which must be met (as pointed out in Quantas's answer below), however what happens when the autopilot breaks?  It is still technically "equipped" with the autopilot that meets the requirements.  Part of our job as pilots is to operate the airplane as efficiently as possible while still remaining safe and legal.  Intimate knowledge of the regulations is essential in order to accomplish that.

About whether or not you can fly with an inoperative autopilot, take a look at §91.180:

§91.180   Operations within airspace designated as Reduced Vertical Separation Minimum airspace.
(a) Except as provided in paragraph (b) of this section, no person may
  operate a civil aircraft in airspace designated as Reduced Vertical
  Separation Minimum (RVSM) airspace unless:

The operator and the operator's aircraft comply with the minimum
  standards of appendix G of this part; and
The operator is authorized by the Administrator or the country of
  registry to conduct such operations.

(b) The Administrator may authorize a deviation from the requirements
  of this section.

You also can't say that your aircraft is allowed to operate in RVSM airspace:

Section 4. RVSM Operations
(a) Each person requesting a clearance to operate within RVSM airspace
  shall correctly annotate the flight plan filed with air traffic
  control with the status of the operator and aircraft with regard to
  RVSM approval. Each operator shall verify RVSM applicability for the
  flight planned route through the appropriate flight planning
  information sources.
(b) No person may show, on the flight plan filed with air traffic
  control, an operator or aircraft as approved for RVSM operations, or
  operate on a route or in an area where RVSM approval is required,
  unless:

The operator is authorized by the Administrator to perform such
  operations; and
The aircraft has been approved and complies with the requirements
  of Section 2 of this appendix.

If it's not operational, the aircraft no longer qualities for RVSM, and therefore must be provided with 2000 feet vertical separation (each way) between other aircraft. Alternatively, ATC can refuse entry into RVSM airspace.
Regarding having the autopilot engaged, Appendix 4 of AC 91-85, Section "5. In-flight Procedures" states:

e. An automatic altitude-control system should be operative and engaged during level cruise, except when circumstances such as the need to retrim the aircraft or turbulence require disengagement. In any event, adherence to cruise altitude should be done by reference to one of the two primary altimeters;

@lnafziger: in its current state, it's unable to do so... But yes, it would have been more obvious if it did explicitly say "all must be operational" or words to that effect.

Okay, so it looks like 91.180 and FAR 91 Appendix G, 4(b)(2) contain the requirement for a working autopilot.  If you add the second reference (and relevant quote) I'll mark this as the correct answer.  Thanks for all of your help!

@lnafziger: since you've edited your question, I've changed my answer accordingly.

@lnafziger: is that better? ;)

@rbp Nice edit, although this is not a mandatory requirement (shall -vs- must and it is an Advisory Circular which is not regulatory).  Good reference though, thanks!

For RVSM, the autopilot (and altimeter) has to be operable, certified for maintaining a tight altitude tolerance, and maintained in an approved RVSM maintenance schedule.
FAA Part 91, appendix G, Section 2.
In the event the autopilot fails at RVSM altitudes, the pilot shall contact ATC and state "Unable RVSM Due Equipment". ATC will provide non-RVSM separation and/or clear the aircraft out of RVSM airspace.
AIM 4-6-8.

Haha, thanks, but that is the link that I posted and says nothing about it being operable.  :)

It says, "The aircraft must be equipped with at least one automatic altitude control system that controls the aircraft altitude—", which implies operational. It could not control the aircraft altitude if it was inop. In addition, the plane's required equipment list almost certainly would not allow flight at RVSM altitudes without autopilot.

Well, your quote is a subitem of "To approve an aircraft group or a nongroup aircraft, the Administrator must find that the aircraft meets the following requirements:".  Note the "to approve" portion, not "to operate" or "to fly" or anything like that.  Also, the autopilot IS listed in the Master MEL (MMEL) and may be inop (I believe for up to three days, but I'm not positive on that).

Also, I appreciate your answer and you looking into this.  I'm just trying to find out for sure and get the "right" answer!

I added AIM info to the answer.

"Also, the autopilot IS listed in the Master MEL (MMEL) and may be inop (I believe for up to three days, but I'm not positive on that)" - That would depend on the aircraft, of course.

I can't trace this back to the CFR's, but I'll tell you that our OpSpecs and MEL's require that the autopilot DOES have to be engaged (and thus, operative) when in level flight in RVSM airspace.
The aircraft is APPROVED to go into RVSM airspace based on the equipment that it has, with an assumption that it all works.  That approval process happens outside of anything that the actual line pilots ever see.  We have our operating manuals, which are driven by Part 121 and our carrier's OpSpecs, and they're pretty clear on the point.  Our MEL likewise says that RVSM operations aren't allowed if both autopilots are deferred, and I strongly suspect that everybody else's manuals say exactly the same thing.
Of course, the exception to all this is that ATC could clear you into the airspace anyway and provide 2000' of separation from everybody else, and at 0300L that might actually work.  And I've heard a few military jets that aren't RVSM approved (old altimeter systems, I think) get that treatment as well.  So the general answer to the question is "no," although the precise answer is "yes, if..."
But generally, no, you need the autopilot engaged while in level flight in RVSM airspace.

Yeah, they let some /A military guys go RVSM sometimes, but you can't file for it and you obviously have to request it.  Usually its aging training aircraft (in my experience) that aren't RVSM certified.

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text:
What additional aircraft equipment is required to fly a US registered airplane in Europe?
If I want to take an airplane to Europe, what additional aircraft equipment is required beyond the US requirements?
For instance, I know that we need 8.33Khz spacing radios, what else is there?
Also, I heard that it will be changing in 2015 to have additional requirements.  What will those be, and will there be any exceptions (ie, can we obtain a waiver)?

You only need 8.33kHz spacing above FL195 in Europe

@PhilippeLeybaert Good to know, but that applies to me!

An overview of ATC related avionics can be found on the Eurocontrol website. There are a couple of things changing in 2015.
The list below includes change to ATC related avionics requirements in 2015.
In addition other avionic requirements not related to ATC are imposed, but that is outside my field of expertise.

Surveillance
Commission Implementing Rule (IR) (EU) No 1207/2011
Commission Implementing Rule (IR) (EU) No 1028/2014 (Amendment of 1207/2011)
ADS-B
ADS-B (1090ES) will be mandated  from 7 January 2017 for aircraft with MTOM > 5700 kg and Max cruise TAS > 250 Kts with an individual  certificate  of  airworthiness  first  issued on or after 8 June 2016. For aircraft certified before 8 June 2016 with the same MTOM and max cruise speed class ADS-B will be mandated after 7 June 2020 .
Applies to all IFR flights in the European Civil Aviation Conference (ECAC) airspace, excluding oversea territories.
Mode-S Elementary Surveillance (ELS)
Mode S ELS will be mandated for all aircraft operating according to Instrument Flight Rules from 8 January 2015
Applies to all IFR flights in the ECAC airspace, excluding oversea territories.
Mode-S Enhanced Surveillance (EHS)
Mode S EHS will be mandated for new aircraft with MTOM > 5700 kg and Max cruise TAS > 250 Kts from 8 January 2015. For existing aircraft in the same MTOM and max cruise speed class Mode S EHS will be mandated after 7 December 2017.
Applies to all IFR flights in the ECAC airspace, excluding oversea territories.

Communication
Commission Implementing Rule (IR)(EU) No 29/2009
Controller-Pilot Data Link Communications (CPDLC)
CPDLC (VDL Mode 2) is mandated above FL285 from 5 February 2015
Applies to all IFR flights in the ECAC airspace, excluding oversea territories.

Safety Enhancements
Commission Implementing Rule (IR) (EU) No 1332/2011
TCAS
From 1 December 2015 TCAS II version 7.1  will be mandated for all aircraft build before March 2012 with MTOM > 5700 kg and Max cruise TAS > 250 Kts operating in EU airspace. Aircraft first certified after 1 March 2012 already need to operate with TCAS II version 7.1.
Outside EU airspace, but within ECAC airspace, TCAS version 7.0 is still allowed.

I really depends on what kind of aircraft we are talking abut. All the additional avionics @DeltaLima already has mentioned correctly effect aircraft with a MTOM of 5700kg or greater. If you think about some smaller G/A planes like a Cherokee or Skyhawk you should consider additional noise abatement. If you don't fulfill some requirements regarding noise abatement you will most probably spend a lot more money on landing fees or even meight be not allowed to land at some airports. I honestly don't know about noise regulations for bigger aircraft, but I guess that the differences between the US and Europe at this point are most significant at light types.

Can you expand a little on the European noise abatement rules/requirements (perhaps with some examples)? Are the additional requirements procedural, or is there equipment that needs to be added/removed/modified to comply?

I will ad least try to, but I only know about the german rules in detail. I would like to provide you with my reference, but unfortunately it's from a German law book - how about your german?? ;) I'll add some of it to myanswer shortly.

I can generally manage to order food and drinks in German without getting myself poisoned - for everything else there's Google Translate :-) I'm mainly interested in the idea of noise abatement equipment as a regulatory construct (in the US most of it is "noise abatement procedures" - I've heard tell that other countries actually require specific equipment/modifications to the aircraft but it's quite literally a foreign concept to me :)

To give you a basic idea: In Germany laws exist that state, that aircraft are either not allowed to create more than a specified ammount of noise dependent on their age, their mass and the way they are driven, ore can only be operated with many restrictions. These restrictions may be different from airpirt to airport and meight even prohibit the operation of the effected aircraf on the field regardless of the day or time (most restrictions are time restrictions or prohibit some kind of operation on specific days of the week) Also airports use the mising certificates to raise the lsnding fees.

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text:
What is required to fly over Cuba enroute to another country?
I understand that you need to get an overflight permit before entering Cuban airspace, even if you aren't landing there.  How do you go about getting permission to overfly them enroute to another country?
Updated now that flights to Cuba are allowed by US operators.  What has changed, and what are the requirements now?  Can we pay them directly yet?

Isn't it small enough that going around it is not very different from avoiding a class B airspace?

@mah: Considering that the island is almost 43,000 square miles (and the airspace is even more) I'm going with no, it isn't the same.  And even if it were, lots of people fly through class B airspace instead of going around it in order to save time and money.  :-)

Is this just a problem for US pilots? I think this question or its answers needs some clarity in that regard.

@called2voyage: Good question.  If I had to guess I would say that anybody needs permission to overfly the country so that you don't get shot down, but a reference would be good to find!

There's a great article here: http://www.universalweather.com/blog/2013/03/understanding-cuban-overflight-permits/

I actually do it all of the time and know that the major international flight planning organizations (Universal, Arinc Direct, Colt, etc.) can all get the permit for you, but am still curious how things work directly with them now that our relationship with Cuba has changed....

The IACC navigation fees are approximately $170 for a small jet, plus there is a service fee to issue. There is a full list at World Air Operations and you can in fact order the permit for Cuba online there too.

I should add - the rules are changing slowly as regards landing in Cuba for US operators - they expect that by mid 2016 it will be open to all. Let's see.

Yep, the 3rd party route is easiest. We've used World Air Ops (Canada) for this in the past, http://www.worldairops.com/permits/cuba.html. For our aircraft (CL601) the Nav fee was around $150.
The application fee $50 or so.

AOPA has a short article about flying over Cuba, it includes the following quote:

It is important for all U.S. pilots and U.S. aircraft owners to know
  that in order to request a[n overflight] permit, or to pay fees to Cuba related to
  your aircraft, you must obtain an OFAC license or retain the services
  of a provider that has an OFAC license

Since OFAC appears to have virtually no web presence, I would assume that using a third-party provider is the most viable option. Another (older) AOPA article mentions one.

Thanks, this is good info, however I'm looking specifically for how to get an overflight.  I.e. from who?  Is there a list of providers?


text:
Where to find Tach hour and clock hour equivalence rpm?
There is a revolution counter built into the face of the Tachometer in most piston powered GA planes.  This counter is calibrated in hours.  Most planes also have a Hobbs meter, which is a clock.
Only at a certain RPM are tach hours equal to clock hours.  This equivalence rpm is different among the various manufacturers and models, and it is published somewhere.  For a Piper Archer II with the standard Lycoming O-360-A4M engine, what is the equivalence RPM, and in what document is it found?  It is not in the Type Certificate Data Sheet (TCDS) for the Archer II (PA-28-181).

As far as I know the only place to get this information is the tachometer specifications (or at least I know Mitchell provides it for their tachometers).
As you noted, it's not on the TCDS, nor have I ever seen it in the (Piper or Lycoming) maintenance manuals. (It is of course possible I've missed it in the maintenance manuals - they're pretty thick books.)
If you are flying around in a plane with a working tachometer and don't know the hour-meter's equivalence speed you can always determine it with a watch: every 6 minutes is 0.1 hours, and when the tach is recording at that rate you've found the equivalence RPM.
(For the Archer I assume it's the same as my Cherokee 180 - around 2300 RPM.)

It's worth noting that while you would think the tach's hour meter would be "accurate" (1:1 correspondence) at typical cruise powers that is often not the case!
  Using the Archer as an example, 65% power cruise at 7,000 feet is around 2500 RPM, so the tach hour meter will be running slightly faster than 1:1 in a 65% power cruise at 7,000 feet.

The watch-check I described above doesn't help you if the reason you need to know this information is your tach has died and you need a replacement - fortunately tachometer manufacturers all know this and publish recommended applications for their tachometers.
Mitchell lists their D1-112-5023 (2300RPM) tach as the appropriate replacement for the PA28 family, which matches up with the watch-test on my Cherokee.

@Vortaq7: Thanks for the answer.  I am not ready to believe that the airplane manufacturers or the engine manufacturers do not specify what the equivalence rpm should be, and leave this up to the Tach manufacturers.  In this highly regulated industry, that doesn't seem likely.  Basically, that's why I asked the question... So again, thanks for the answer and let's see if somebody has better detail on this one.

@SkipMiller I agree this seems like something that should logically be in either the airframe or engine service manual (and I was pretty baffled when my mechanic and I couldn't find it except by looking at the specs of "approved replacement" tachs). I'm hoping someone comes along and says "You can find it over here!" - it would be useful to know where to look for a general reference!


text:
I accidentally deviated from an ATC instruction as a student pilot. How bad was it?
Here's the scenario: I was a student pilot on inbound for landing at my home airport on my final solo cross country flight I needed before doing a checkride.
At roughly 8 miles out to the north west, I established contact with the tower and was told to "enter left base, runway 7, report 3 miles out." I interpreted the "report 3 miles out" as to give the tower a call when I was 3 miles away from the field, ie, when my GPS indicated I was 3 miles from the field.
Now, it was the most windy day I had flown solo in so far (15kt gusts) so I wanted to make sure I had ample time to line up with the runway on final and get a feeling for how the winds were blowing since the ATIS reported them as being variable in direction.
That said, what I ended up doing was making a wide base, except apparently I made it a little too wide because the GPS did not indicate I was 3 miles from the field until I was on final. At this point, I called the tower, reported I was on a 3 mile final and was given clearance to land. After landing, I still had no idea I had done anything incorrectly as the controller made no indication to me.
A few hours after I landed, my CFI sent me a text message asking me how "report a 3 mile base" meant "report a 3 mile final and fly a straight in approach." I'm not sure if he was on the frequency when it happened or if the tower controller called him after the fact and told him about it because I was told to "report 3 miles out", not "report 3 mile base."
I completely understand that I made my base leg too wide and that caused me to deviate from an ATC instruction. What I'm wondering is how bad of a screw up is this? My CFI's reaction was one of legitimate anger and it makes me want to stay on the ground for a while.

Did you speak with you CFI about the mistake in detail? There is nothing as bad as making a mistake and being unable to learn from it.

@ratchetfreak I'm sure it's going to come up the next time I fly with him, but right now I'm looking for some outside info because he wasn't exactly being polite about it.

@user2207 I cannot answer your question but only commenting about your last sentence. You might have, probably did cause some inconvenience so you've to learn from it. Don't get too upset about CFI. You are very close to not seeing him too often anyway. You can get a better CFII for the next phase.

I may be mistaken, but I'm pretty sure the tower gives you a number to call if you've really screwed something up.  And then you get to talk to someone from the FAA about it.  If you didn't get a number...  Not to downplay your mistake, I'm just sayin'.

if you are worried then contact him before you go flying again, a good CFI will be able to explain what you should have done

I don't know where you're training, but consider contacting the tower, explain the situation and try to arrange a visit. I am sure they're happy to explain their side of the game and their expectations.

@JayCarr Not always. I had a student freeze up and mostly stop responding to tower the other day... Tower told him to tell me to call them. I had no idea what their number was!

Well, you screwed up, but nobody got hurt, no metal was bent, and since the tower didn't yell at you presumably you didn't obviously endanger anyone's safety (though there's always some level of risk when an aircraft isn't where the tower expects it to be).
As far as deviations go, that's not good, but it's not terrible. The tower was probably expecting you to report 3 miles out, continuing in to about a mile from the field for your downwind.
Schedule an extra half hour of ground time with your CFI before your next flight to talk about what happened. Also take the time to fill out an ASRS report explaining what happened and why (It's probably unnecessary in this case, as a student the tower will almost certainly be satisfied with you getting "a good talking-to" from your instructor, but it's a good way to learn how that system works.)

There are a couple of other things you might want to do on your next few training flights:

Spend some time getting comfortable in the pattern on windy days.
You should be comfortable in a tighter pattern than 3 miles, even on a windy day (see my next item for why). This takes practice, and fortunately for you it's spring (at least in the USA) so there are plenty of windy days in most of the country!
Practice some engine-out approaches to get a feel for your plane's glide performance.
A base leg 3 miles out in a typical GA trainer is very wide -- Remember you generally want to be able to make some spot on the runway if your engine quits on downwind, and you probably can't do that from 1000 feet AGL at 3 miles out.
Take a few laps around the pattern and have your instructor pull the power at various points so you have a feeling for how the energy management works out - this will give you a good feel for how wide your pattern should be.
Turn the GPS off and practice flying visually.
The GPS is one link link in your error chain, but I think it's a big one: If you were flying visually and relying on landmarks to judge your distance rather than the 3 mile alert from your GPS you might have realized "Hey, I'm entering downwind - I should tell the tower!"

Biggest take away here is the lousy phraseology from ATC, especially with a student.  Are you guys in the US?  Do you have/use the prefix "TYRO"?

@Simon no, but student pilots can identify themselves as such on first contact with the controller. There's no requirement to do so, and I never did, but many do, and it helps the controllers go easy on them.

@BretCopeland  Thanks.  Personally, if I'd been the CFI, I would have invited the controller to a "tea, no biscuits" meeting along the lines of "if you want people to precisely follow your instructions, then issue precise instructions". That said, it does seem like the only person with a burr up his a** is the CFI.

I already stated my opinion about the matter in chat http://chat.stackexchange.com/transcript/message/15163821#15163821

@Simon 100% agree on the less-than-ideal instructions from the tower - I'm pretty sure I've guessed their intention, but I'm used to (and prefer) less ambiguous instructions :)

The tower said, "enter left base," so a downwind was not expected.  It also said, "report 3 miles out," not, "report 3 mile base," so (assuming the OP's quoting is accurate) there was no violation, the CFI overheard the transmission, and the CFI was wrong.

Count me as another vote for "the OP did nothing wrong". I'm not seeing a problem with what they did, and the tower didn't comment, so I don't believe they did either. I'd talk to my instructor, and one thing I've learned, don't argue, see if they have anything instructive to say and accept the feedback with respect, but don't take it personally. YOU were PIC, not them, even though you're a student you still have more knowledge of the sitatution that occurred than an instructor that wasn't in the plane.

(I recognize that this question is now 3 years old, but since GreenAsJade resurrected it...!)
If we're speaking about controllers working at a tower at your own airport, it might be worthwhile to call the tower on the phone, identify yourself as the pilot of N1234X, and ask if you could visit them.  Of course, be respectful of their time (don't call when there's a lot of traffic in the area!).  Depending on the field, you may actually get to visit the tower, a terrific experience for any pilot of any experience level! (note:  perhaps this would no longer be permitted post 9/11).
The first time I did this was after screwing up at my home field, or, at least, they sounded annoyed on the radio, and I wanted to clear things up once on the ground.  Some observations:
1)  Few controllers are pilots, so they don't always know what's going on. They have a 'godlike' view with their radar screen, but you the pilot have a very different environment and things can be happening fast. That's not an excuse, it just is, which is why we train and practice so much.  Controllers can get overloaded too, of course, and our boneheaded mistakes make their problems worse, and can cause accidents, which is the controller's #1 job to prevent!
2)  Controllers are curious about us pilots and we should be curious about them.  I was surprised that they had as many questions about flying an airplane as I had for them about being on their end of the mike.
3)  It's a partnership!  Controllers and pilots work together to do this dance of aviation efficiently and safely.  We're in this together!  Honestly, if a controller doesn't feel loyalty to us pilots, they're in the wrong business.
4)  We owe them loyalty, too!  (Climb) Confess, Comply.  Don't have a chip on your shoulder.  You want to learn and do your part to be safe, be safe for others too.
After doing this at my home field (the one I learned at many years ago), I had a very different relationship with the controllers.  I visited more than once and learned a ton! They knew who I was and I knew them.  Seriously, I got better handling and occasional hand holding as a newly minted pilot.  Later, I repeated this at a new home field after moving far across the country, and it was as rewarding as before.  In other situations, I've just called a Flight Service briefer (800-WXBrief) during off hours to discuss things like this (evenings tend to be slow).  AOPA also has great resources to call.
Maybe you can't visit towers any more - I don't know - but you could always approach your airport manager about setting up a discussion session with the guys in the tower, say some evening after dinner.  If you do that, work hard to promote it and you'll have an amazing evening that will benefit everybody involved.  Promote aviation, promote understanding, and promote safety.
Clear skies and tailwinds.

Welcome to Aviation.SE and a great answer to begin with.  Have some rep. So many simple human truths in what you say.

+1 for great advice, it's what is needed, though I would point out you didn't actually address the main question.

Good point! So maybe more directly to the question... The OP was relying too much on GPS and too little on the intent of the instruction form the controller. We didn't have no stinking GPSs way back when, so the only way to "report 3 miles" was by intimate familiarity with the airport & ground references. Other than that, what "report 3 miles" really means is to tell the controller that you are in the immediate vicinity of the airport & actually have the field in sight.  If you're dancing around at 4 miles but have yourself oriented on the field, that's information to let the controller know.

I also agree with others that the instructor handled his response poorly. He acted like the student made him look bad. Heck, all of us have done stupid things in the air. Step1 is to be honest with yourself (confess, comply). Step 2 is to be grateful for it turning out ok. And Step 3 is to work to improve.in the future. Be safe!

It's not really bad at all.  How do we know?  Because the ATC didn't intervene or question you.
What emerges for me out of this report is that you need a new CFI. Getting angry at a student's innocent mistake is bad.   In particular if it is not something you've been cautioned about before (have you?).
Communicating angry feedback by text is even worse. A good CFI would have waited till they had a chance to speak to you, and started with asking you what happened, not started with an attack on you.

I don't think you necessarily did anything wrong.
First, like GreenAsJade said, tower didn't yell at you in the moment. This is not incontrovertible evidence of legality or correctness, but it's a pretty strong piece of evidence.
More importantly, "report three miles out" is not a standard pattern entry. Here are the prescribed pattern entries from the ATC order, JO 7110.65, 3–10–1 a.

3–10–1 LANDING INFORMATION
[...] Issue landing information by including the following:
a. Specific traffic pattern information (may be omitted if the aircraft is to circle the airport to the left).
PHRASEOLOGY-
ENTER LEFT/RIGHT BASE.
STRAIGHT-IN.
MAKE STRAIGHT-IN.
STRAIGHT-IN APPROVED.
RIGHT TRAFFIC.
MAKE RIGHT TRAFFIC.
RIGHT TRAFFIC APPROVED.
CONTINUE.
NOTE-
Additional information should normally be issued with instructions to continue. Example: “continue, report one mile final”; “continue, expect landing clearance two mile final”; etc.

Note that phraseology such as "report three-mile left base" is not prescribed. [See addendum below.] In this situation I agree that that was probably the controller's intention (set up for a "normal" base, i.e. for a one-mile final, and report when three miles "out") but even in this case what does "three miles out" mean—three miles from the runway threshold, meaning two miles from final, or three miles from final itself? Who knows? It isn't standard phraseology. You entered a wide left base and ended up setting up for a three-plus-mile final, and reported three miles "out" from the threshold. That may have been what the controller meant all along. We don't know.
In cases like these the controller could be more explicit by saying "enter a wide left base, report three mile final" or "enter base for a standard final, report three miles from final" or "proceed direct to a three-mile final" or other such instructions. Absent such clear instructions, I don't think it was necessarily incorrect for you to a) enter a left base and b) report three miles away from the threshold, which is what you did. If there was traffic to follow on a longer final, for example, the controller could have said to enter an extended downwind. Or alternatively if the controller had a departure almost-but-not-quite ready they could have not cared how you arrived at the runway as long as you gave a heads-up when three miles away.

Addendum: Effective October 5th, 2023, the Pilot/Controller Glossary term for "TRAFFIC PATTERN" now includes the following notes regarding "report base" and "report final."

NOTE-
ATC may instruct a pilot to report a “2−mile left base” to Runway 22. This instruction means that the pilot is expected to maneuver their aircraft into a left base leg that will intercept a straight−in final 2 miles from the approach end of Runway 22 and advise ATC.

NOTE-
ATC may instruct a pilot to report “5−mile final” to Runway 22. This instruction means that the pilot should maneuver their aircraft onto a straight−in final and advise ATC when they are five miles from the approach end of Runway 22.

Even under this newly-codified meaning, the instruction was neither of the above but a more generic (and ambiguous) "report three miles out."

It happens and good controllers will be able to work with you.  I don't know of any pilots who haven't screwed up a radio instruction a time or two.  It could be worse; you could be this guy.

On a more serious note and FYI, the tower wanted you to enter a long base for the runway and report three miles out while on base.  Will it result in anything aside from a little embarrassment and a CFI razzing you about it?  No.  Had it resulted in an incident or an accident then yes you could be found liable for it and suffer civil or criminal penalties.
Back when I was a freshly minted Cessna driver I had a tendency to be a little dyslexic and turn left when I was instructed to turn right, once nearly straying into a block of restricted airspace near an airport I was flying laps in a traffic pattern at.  This made for a colorful conversation between the tower and myself, but nothing more came of it.  Everybody makes mistakes and any pilot who tells you they don't is full of crap.


text:
Why must the long cross-country flight for a commercial rating be solo?
Assuming I am interpreting the below FAR correctly, one must either be solo, or have an instructor present to complete the long cross country requirement. More specifically, it seems to me that you could meet the requirements with a passenger present if an instructor is on board.

§61.129   Aeronautical experience.
(4) Ten hours of solo flight time in a single engine airplane or 10 hours of flight time performing the duties of pilot in command in a single engine airplane with an authorized instructor on board (either of which may be credited towards the flight time requirement under paragraph (a)(2) of this section), on the areas of operation listed under §61.127(b)(1) that include—
(i) One cross-country flight of not less than 300 nautical miles total distance, with landings at a minimum of three points, one of which is a straight-line distance of at least 250 nautical miles from the original departure point.

I'm trying to understand what the purpose of the solo requirement is, and how it could be alternatively achieved without being solo, but only if an instructor is onboard.
It's clearly not for safety of the passenger, since, as a private pilot, its completely legal for me to make the very same flight with a passenger; I just can't use it to meet the commercial requirement quoted above. Why not? And how could adding an instructor to the plane make any difference?

They addressed this question at http://www.askacfi.com/5172/aeronautical-experience-commercial-pilots-license-asel-solo-requirements.htm. For insurance purposes, it is often not possible to solo in a twin or helicopter and for consistency, they extended it to single engine. It also allows you to count time working on your IFR toward the commercial. e.g. if your long IFR cross-country can count for your commercial as well.

The askcfi link doesn't answer the question why the x-country must be done solo (except where they waive the requirement). What is the harm in allowing the long cross country occur with a passenger onboard for the purpose of this requirement?

I got this answer to my question from a CFI...
The idea behind the solo requirement is to assure the pilot can accomplish the trip unassisted. Other passengers are permitted if an instructor is present because the instructor will assure that the passengers do not assist with the flight.

I'm not sure I buy this answer, but it's the best I've heard so far.

I've always believed that the idea behind the solo requirement is to develop confidence as a pilot.  When the flight is all up to you, the idea is that you will rise (pun intended) to the occasion, and realize that you are Pilot in Command, you are the only one in the airplane so it is really obvious that you are final authority and responsibility for the operation and safety of the flight.
From a legal perspective, I think the answer to your question might be found in this response from the FAA.

Because this flight time is a substitute for solo flight time, the
pilot is not receiving instruction and therefore cannot log this time
as dual instruction received. The pilot can log the time to meet the
requirements of § 61. 129(a)(4) and log total flight time. Section
61.51 (e) prescribes the requirements for logging PIC time. The pilot could log PIC time under § 61.51(e)(l)(i) if the pilot has a private
pilot certificate with the appropriate ratings for the aircraft.
Otherwise, the pilot cannot log PIC time. None of the other § 61.51(e)
logging provisions are applicable to your scenario. However, § 61. 129(a)(4) permits crediting of the time toward the 100 hours of PIC time required for
the commercial pilot certificate under § 61.129(a)(2). The logbook entry should accurately
reflect the provision under which the flight time is logged.

So the wording in 61.129 isn't really about being alone in the airplane, it looks like this is actually to clarify that that the commercial pilot student (in this case) needs to actually conduct the flight as PIC (with all the responsibilities therein - see below), and if the CFI goes with the CPL student, the CFI cannot log it as PIC time (as they normally would when acting as a CFI), and the time would not be logged as dual received for the Commercial Student, but just straight PIC time.
As a reminder PIC is defined in 14 CFR § 1.1:

Pilot in command means the person who:

Has final authority and responsibility for the operation and
safety of the flight;
Has been designated as pilot in command
before or during the flight; and
Holds the appropriate category,
class, and type rating, if appropriate, for the conduct of the
flight.

As a final note, I think it gets confusing because 61.87(a) defines solo flight, but only for subpart 87, which is clearly talking about students who have not obtained their private pilot certificate yet:

The term “solo flight” as used in this subpart means that flight time
during which a student pilot is the sole occupant of the aircraft...

The same definition does not exist in 61.129 (Aeronautical Experience for Commercial Pilot Applicants).  Noticeably absent from the regulation, however, is the mention of any passengers, so I think the choices are a) the pilot is the sole occupant of the airplane, or b) the pilot is making the flight with their flight instructor, however, the flight instructor is essentially a passenger (unable to log PIC or dual-given time), and the pilot must log the flight as PIC.
I believe this idea that it must be either solo or with your CFI is further confirmed by this interpretation from 2016:

a pilot must choose to log all ten hours as solo flight
time in a single engine airplane or, in the alternative, log all ten hours performing the duties
of a pilot in command in a single engine airplane with an authorized instructor on board. A
combination of hours is not permissible under the rule.

This means you must plan for the 10 hours in 61.129(4) to either all be solo, or all be with an authorized instructor (who is not acting as PIC).

https://www.faa.gov/about/office_org/headquarters_offices/agc/practice_areas/regulations/interpretations/Data/interps/2007/Olshock-PanAm3%20-%20(2007)%20Legal%20Interpretation.pdf <- Just curious what your thoughts are on this interpretation. The last sentence: The instructor may also permit others on board for instructional purposes.

Wow, that certainly seems worded in a way that isn't totally clear, however, I still believe it's one or the other. Either you're doing all 10 hours solo, or you're doing the 10 hours with an authorized instructor not acting as PIC and, should the instructor so deem, you can take along additional people for instructional purposes. I understand these pilot mills are cranking a bunch of people through, but my personal opinion (and true, I don't fly twins with a goal of the airlines), is that solo means by yourself, and I think the mental toughness developed as the sole occupant is a benefit.

What they're really after here is can you flight plan a trip to a different region of a country or continent and successfully navigate it.  This requires more through flight preparation to an unfamiliar airport or where the weather may be different or changing from you time of departure to your ETA.  It also forces you to cope with changing conditions e.g. day into night, etc.


text:
Why are these carrier aircraft landing with the canopy open?
I was reading this answer here Aviation.SE, which includes the following video of multiple F7U-3 Cutlasses landing aboard the USS Hancock in 1955 (warning, video includes footage of a fatal rampstrike):

I notice that each and every pilot is landing with the canopy open. Why is this?
I'm not a pilot, so these are uneducated guesses:
It could be opened for visibility reasons, except I'm guessing it'd be forward visibility that's be most important, and the sliding canopy doesn't do that any obvious favors. And according to Wikipedia, the plane's high cockpit was already designed for good visibility for carrier landings.
My other guess would be that the canopy is opened in case of a bad landing/fire (less bad than the rampstrike later in the video), and the pilot has to get out in a hurry. But I doubt it'd make a huge difference as the pilot's (presumably) still strapped in. And if he can open the canopy while on approach to a carrier landing, it's probably fairly straightforward.
Last guess would be that it's in case the pilot has to eject, yet he should be able to do that, open canopy or no. Besides, the seat would still hit the canopy upon ejection, it seems - maybe just-in-case to avoid the pilot's head hitting first?

Because it is the standard operating procedure, not only for this aircraft, but also for others. In the book U.S. Naval Air Superiority: Development of Shipborne Jet Fighters - 1943-1962, [Tommy H. Thomason notes](By Tommy H. Thomason):

Leaving the canopy open for landings and takeoffs would still be standard for many years as it facilitated egress in the event of a water landing.

Here's the Grumman F9F Panther, one of Navy's first jet fighters landing with its canopy open:

Grumman F9F-5 Panther, Bu. No. 126034, of VF-781, catches an arresting cable when landing aboard USS Oriskany (CVA-34), 15 November 1952. (U.S. Navy); image from thisdayinaviation.com
This followed through the time of Cutlass, as thanlont.blogspot.in notes:

The ... F7U pilots all have their canopies open for landing. Although open canopies for carrier takeoffs and landings had been standard since canopies were introduced, this became pilot's choice on straight-deck carriers at some point following the addition of the barricade ... after an incident or two when the upper strap of the barricade went into the cockpit of a crashing jet. Note that the FJ-3s are taking off with open canopies.

Thanks for the answer. The last source is written a little strangely, though: I'd imagine it should be "pilot's choice until an incident where a barricade strap went into the cockpit", after which they were kept closed. I can easily see how the barricade straps could hit the pilot if the canopy's open

With a 0-0 ejection seat it's not necessary to open it as you can pull the eject as soon as you know that you are going to end up in the water.

@ratchetfreak It would be preferrable to just undo your harness and swim out. Ejecting is a rough event and older ejection systems were not meant to be used at low altitudes. Usually it meant getting flung up 200+ feet in the air and then hitting the water still strapped into your ejection seat, wrapped in your chute (that didn't fully deploy), and you may have broken arms or back injuries.

@RonBeyer that's why I mentioned 0-0 (zero altitude, zero airspeed)

@ratchetfreak even a 0-0 seat would give a rather wild ride with high chance of spinal damage when used. I think the main reason the canopy is now kept closed is more the higher speeds rather than the availability (alone) of 0-0 seats.

@Flambino I understood the quote to be that after the pilot strike incidents the pilots could choose to leave the canopy open (facilitating exit in case of water landing) or closed (preventing barricade strike).

@DJClayworth ah right, that makes sense

I'm pretty sure that no 1950s vintage ejection seats were zero-zero.

@MichaelHall they weren't, that comment is rather an attempt to explain why the procedure changed.

The above answers are right; it's done to facilitate quick evacuation of a jet in case of an emergency or a liquid landing.  Modern carrier jets use jettisonable canopies along with a zero-zero ejection seat for quick evac and rescue, so having the canopy unlocked and open is no longer a requirement when coming aboard.  Graphic example of what can happen if the canopy was not unlocked in an emergency was this tragedy aboard the British carrier HMS Victorious in 1958.


text:
How is GPS RAIM availability calculated?
I recently had someone ask me if there was a GPS RAIM availability calculator available for the iPad.  There isn't, but it got me thinking that I could write one.  After doing some searching, I can't find a good explanation of how to calculate RAIM availability, so am looking for the formulas used to calculate it for a specific route.
I want this to be an offline tool, so the calculations need to be complete, rather than relying on a website for the information.

The website that Ralgha points out is indeed the one to look at for the US. They also provide a SOAP interface should you want to create your own app for the IPAD.
For RAIM to be available, you need to check firstly that at least 5 satellites (Space Vehicles in GPS language) are visible from you position, or 4 if your RAIM algorithm uses Baro-aiding. They have to be well above the horizon. How much depends on your satellite receiver, the FAA uses 5 degrees on their website. There are some receivers that use a masking angle of only 3 degrees.
Orbital equations can be taken from the GPS interface control document, section 30.3.3.1.3. They take almanac data as input. Apart from the Space Vehicle orbits, you also need to take into account their health from the NANU's.
With the satellites available, you need to calculate the RAIM containment bound. This is the maximum size that a position error can grow due to a faulty satellite signal without the RAIM algorithm noticing it within 10 seconds (with a 99.9% probability). If that containment bound is more than 1 nautical mile, RAIM is said to be unavailable for terminal procedures. For NPA a 0.3 nautical mile radius is used.
The containment bound depends very much on the geometry of the satellites, more that on the number of satellites available.
The problem with the RAIM algorithms is that they aren't standardized. There are several ways to perform RAIM and because GPS manufacturers use proprietary solutions there is little information available to the public. So calculating the containment bound is where you will get stuck.
So there is no easy way to implement RAIM prediction on an IPad, apart from using the FAA website.
Europe has also a RAIM prediction website; AUGUR.

Good info, but I want to be able to do this offline so don't want to rely on the SOAP interface.  I'll update my question with that

Well, than you're up for some very serious mathematics. I'd like to help out, but as far as I know there are no RAIM algorithms simply available to the public.

Hmm, I figured that surely someone would have them (although I haven't been able to find any either, lol).

These algorithms are carefully kept company secrets apparently

I know there are basically two ways to do it, but I have not done the full math on either. The concept is quite complex and involves geometry and a lot of probabilistic.

RAIM availability calculations are simply checking to see if at least 5 satellites will be visible, that's all it is.  You'll need the orbital equations to calculate that though.  It would probably be easier to pull data from one of the websites that provide RAIM information. http://www.raimprediction.net is the FAA's site.

Details of RAIM calculation is explained in the paper  :
GPS EASY Suite II: easy13 - RAIM by Kai Borre
http://www.insidegnss.com/auto/julyaug09-borre.pdf
Also the author gives a Matlab implementation.
Hope it helps.

could you try to summirize it briefly in your answer?

Interesting article, but it seems to calculate RAIM as part of the position calculation, not RAIM availability.


text:
Which aircraft maintenance repairs require a test flight?
14 CFR 91.407 requires an "Operational Check Flight" of an aircraft before passengers may be carried in certain situations:

§91.407   Operation after maintenance, preventive maintenance,
  rebuilding, or alteration.
...
(b) No person may carry any person (other than crewmembers) in an
  aircraft that has been maintained, rebuilt, or altered in a manner
  that may have appreciably changed its flight characteristics or
  substantially affected its operation in flight until an appropriately
  rated pilot with at least a private pilot certificate flies the
  aircraft, makes an operational check of the maintenance performed or
  alteration made, and logs the flight in the aircraft records.
...

Does the FAA have any guidance that includes examples which better explain the bolded section from the regulation? It seems like that could be open to interpretation which could lead to different people having different ideas about when an operational check is required.
For example, is one required for routine maintenance like an engine change or prop change?  What about a flight control change or a flap change?  A new paint job (including the flight controls)?

I've been in aircraft maintenance for over 15 years, and have worked about 10 different types of narrow and wide body aircraft, and have never once seen a maintenance manual direct me to test fly an aircraft.
There is a reason for this, though. Repairs done during routine maintenance are designed by the manufacturer such that the repair itself makes the aircraft airworthy. That is usually part of the manufacturing and STC process, if I'm not mistaken.
That being said, it's not entirely uncommon to have maintenance control or even maintenance management request a test flight. Usually this is done for troubleshooting or for repair verification. This is largely due to the fact that there are some problems that maintenance cannot duplicate on the ground. For example, I recently worked an airplane whose window heat failed at the top of descent about once every ten or eleven flights. I can simulate a lot of things on the ground, but what I can't simulate is the actual descent of the aircraft at about 37,000 feet! The problem had been ongoing for four or five months, but was sporadic enough not to trigger any alarms in the analysts office. It was only when you paid careful attention to the history of the problem that you realized it had major issues.
Due to regulatory requirements, and the way our GMM is written, if the aircraft had another occurrence on the next flight, it'd be "dead" at the next station it landed with no MEL relief. We made a repair, but it was really only a guess because there were no actual signs of wear/fatigue/damage and everything tested normally. Management requested a test flight, and asked the test crew to run it through the wringer, to see if it would fail.
On the other hand, there are certain systems that may require flight crew verification during flight prior to recertification. An auto land system that has had chronic failures may require the flight crew to perform an automatic landing before it can be recertified back to full CAT III landing status. But, this can often be done on a revenue flight, and is often not a dedicated flight meant to specifically test the system.
There is also the rare case in which major structural repairs may require a test flight. I once saw a wide body aircraft that had a tail strike on landing. The damage was so severe, it literally twisted part of the empennage. In order to be repaired, our company required major involvement from the aircraft manufacturer. The manufacturer did provide a repair, but for obvious reasons, the engineers actually mandated several test flights afterward.
However, as far as I know, there is no regulatory requirement which says that a certain repair requires a test flight. From what I've seen, and perhaps this may sound awful, you kind of "know" when an airplane needs a test flight.

"window heat failed at the top of descent about once every ten or eleven flights... We made a repair... Management requested a test flight" -- presumably a test flight that repeated the descent phase many, many times? It takes a lot of tests to confirm a repair to something that was already working 90% of the time.

@nanoman I hate that I missed this comment, but yes, they will fly for several hours through multiple ascents and descents. Believe it or not, there is a predictability to most of these things. Usually, when we say it happens only every 10 or 11 flights, it’s actually pretty accurate. I’ve seen this time and again where you can almost pinpoint the flight it’ll fail on. I wish I could give a better explanation as to why, but I don’t really have an answer. Brownian Motion and/or magic is my explanation!

I found this on a website about STC Certificates and aircraft modifications:

a. Applicant Flight testing precedes issuance of the TIA. The FAA will >review the applicants flight test reports and repeat some or all of the >tests as necessary. These repeated tests will be identified and performed >per the FAA issued TIA.
b. FAA will perform flight tests for modifications which could affect the >aircraft's performance, flight characteristics, powerplant operation, >and/or overall handling qualities. Changes to systems, equipment, >instrumentation, and flight manuals may also require flight tests. Any >modification which may affect the noise signature and/or navigation of the >aircraft (including performance changes) will usually require fight >testing. The FAA project engineer can provide general information on the >types of tests which may be required.
NOTE: Successful completion of the TIA tests by the FAA is one of the final >steps to STC issuance.
c. Applicant testing.
(1) Research and development flight tests are to ensure the design changes >are in compliance with the applicable 14 CFR's. The FAA will not >participate in or witness these tests. However, the FAA will discuss and >provide general guidance in order that such tests can be made meaningful >and safe. Alternatively, a Flight Test Pilot DER may be utilized to perform >such tests.
(2) Flight test proposals are based on the knowledge of the modification >and development tests. The proposal should be based on the certification basis and include recommended tests, instrumentation to be used, necessary safety equipment, data acquisition, and reduction methods. Upon approval of the test proposal, descriptive and compliance data, and conformity established with the data, the FAA will issue a TIA. FAA flight test personnel should then be contacted to assure that potential hazards are recognized, the required test methods and criteria are understood, and for concurrence.
NOTE: An applicant's flight test report should be submitted to the FAA for review upon successful completion of the inspection and test requirements equivalent to those required in the TIA.
d. FAA testing may include repeating of tests, partially or in their entirety, to verify compliance to the certification requirements. FAA testing may be accomplished by an FAA pilot or an authorized DER flight test pilot.
e. Installation Conformity inspection of the modified aircraft to be used for flight tests will be performed by the FAA or FAA designee prior to FAA testing. If discrepancies are found, they should be corrected and any test which could have been influenced may be repeated before further tests are performed by the FAA.
f. Aircraft weight and the Center of Gravity (CG) location that is current and accurate is extremely important to assure the modified aircraft can be loaded to the critical weight and CG limits for flight testing. The aircraft to be used for official flight tests should be weighed and witnessed by an FAA representative before testing begins. The resulting weight and balance determination will be carefully checked by the FAA and, when found to be accurate, will be used for all subsequent flight test weight and CG calculations.
g. Ballast necessary for flight testing should be securely restrained in such a manner as to withstand the inertial loads resulting from a survivable emergency landing. The preferred form for ballast is small, solid pieces of a high density metal (lead, cast iron, steel, or depleted uranium) fixed to the structure or in a suitable container that is fixed. Using passengers as ballast is not acceptable.
h. Instrument calibration, when required, should be accomplished by an approved instrument repair inspector prior to the FAA flight test program with calibrated cards provided. Types of instruments to be calibrated may include: altimeters, tachometers, temperature gauges, airspeed indicators, etc. Calibrations should be performed within 3 months of the test. However, on critical items, this requirement may be 30 days.
NOTE: Usually, the entire airspeed system is calibrated before flight testing.
i. Rapid emergency egress provisions will be demonstrated to the FAA inspector and pilot for acceptability prior to FAA flight tests. Parachutes will be provided to the FAA, if required.
j. Experimental Airworthiness Certificates, or special flight permits, are issued before operation for any aircraft which does not have a valid TC, or does not conform to its TC. Although the operations may eventually lead to a TC, they may be conducted only as a matter of research, or to show compliance to the appropriate 14 CFR.
k. Flight manual supplements, or if an FAA approved Aircraft Flight Manual (AFM) does not exist, a supplemental flight manual, if required, will be provided to the pilot as a result of the modification, regardless of the method used on the original aircraft. A draft flight manual should be provided to the FAA prior to any flight tests. After FAA flight testing, the draft manual should be finalized and submitted for FAA review and approval. A guide for the format and preparing of a supplemental flight manual is provided in appendix 5 of AC 23-8A, AC 27-1, and AC 29-28.
NOTE: The aircraft TCDS should be checked for identification of the FAA approved Aircraft Flight Manual, if appropriate. TCDS of many older aircraft state placards and markings are required (in lieu of a flight manual). Manufacturer owners' manuals may not be FAA approved.

Here is the link to the page: http://www.astech-engineering.com/systems/avionics/aircraft/faastcprocess8.html

Thanks, installation of an STC is one type of maintenance that could require a test flight, but what about "normal" maintenance repairs? I have clarified the question, thank you for this info though!

What are STC maintenance

STC is a major repair to something that affects they flying condition of an airplane.


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Are children safe when seated in lap during a flight?
We would never consider putting an infant or toddler into a car without a carseat, but we don't hesitate to do exactly this when getting onto a large airplane.
If you aren't aware of the concept of a lap child, this is a child, typically under 2 years of age, who can board an airplane without an assigned seat and must be held by a parent/guardian for the duration of the flight (including the takeoff and landing). The only safety consideration is that the lap child must be seated in a row with adequate O2 masks in case of depressurization (some rows have more masks than seats).
I have always considered this to be an unsafe practice, but have never had data to back that up. It seems to me that holding on to a 20 lbs child when subject to strong turbulence or unexpected maneuvering would be difficult. While not common, adults are occasionally severely injured in these events but I've never noted a lap child being hurt.
Does anyone know of instances where a lap child was injured during a flight? I'm not interested in instances where everyone is hurt but rather instances that having been secured in a car seat would reasonably have prevented the injury.

strong turbulence isn't bad if you have a good grip, a crash is where it's at

@ratchetfreak Moderate turbulence, maybe. Severe turbulence (the kind that actually injures cabin crew) on the other hand may turn your child into a projectile...

Here's the database search page for the NTSB, "lap child" turned up a few results.  I'll look through them later, but I thought I'd link the site just in case you find it useful: http://www.ntsb.gov/aviationquery/

Actually some of do hesitate doing this. To the extent when flying with my 2yr old child we paid full rate for his own seat on the aircraft and wrote in advance to check that we could use the car seat on his seat. When we boarded the aircraft the air crew were adamant that he must go on an adults lap for the take off and landing phase but when the seatbelt sign was out he could sit in his car seat!!! I nearly got thrown off the aircraft for causing trouble trying to explain that he was safer in the car seat than on a lap belt.

I recall seeing a TV program once (I think it was Are We Scaring Ourselves to Death -- I'll have to watch it later) that suggested requiring children to have their own seats was "statistical homicide". The idea is that the additional expense would cause more parents to drive, which is more dangerous than flying.

The injury rate for lap-children in airplanes is significantly safer than the injury rate for car-seated children in cars.   The proper use of regulation/time/technology/wisdom would be to improve the safety of carseats, not airplanes. (pretty much restating what Fred Larson said)

Your instincts are correct, or at least the NTSB agrees with you - they don't like the idea of "Lap Children" on aircraft, and they've come out and said as much in this Safety Alert.
They reiterated that position again in a 2010 letter to the FAA which includes a number of incidents from NTSB investiations, including:

… on July 19, 1989, United Airlines flight 232 crashed during an attempted emergency landing at Sioux City, Iowa, after the fragmentation and separation of an engine fan disk. Of the 296 airplane occupants, 111 were killed, 47 received serious injuries, 125 received minor injuries, and 13 were not injured. Four children, ages 11 to 26 months,17 were aboard the airplane and were being held by adults. A 23-month-old child was killed, and the other three children received minor injuries. The parents of the four lap-held children were instructed to place their children on the cabin floor and hold them in that position while the adults assumed the protective brace position. After the accident, three of the parents reported that they were unable to hold onto their children during the accident sequence.

and

… USAir flight 1016 in Charlotte, North Carolina. The flight crew decided to continue an approach into severe convective activity and was executing a missed approach when the airplane collided with trees and a private residence near the airport. Of the 57 airplane occupants, 37 were killed, 16 received serious injuries, and 4 received minor injuries. Among those occupants who were killed was a 9-month-old child who was held by her mother on her lap. The child’s mother survived the accident but was unable to hold onto her child during the impact sequence, and the child struck several seats. The NTSB believed that the child might not have sustained fatal injuries if she had been properly restrained in a child restraint system.

Granted both of these were pretty severe accidents, but the NTSB investigators found that the lack of restraints was potentially a major contributing factor to the injuries of children on these flights.

In that same letter the NTSB also notes that unrestrained children are not just a hazard to themselves in a crash:

Passengers are required to securely stow all carry-on baggage during takeoff and landing because of the potential risk of injury to other passengers in the event of an unexpected hazardous encounter. However, passengers are permitted to hold a child of equal size and weight in their lap. When children under 2 years of age are not required to be restrained for their own safety, the safety of their fellow passengers also becomes an issue.

See here for more NTSB pronouncements on the subject of child safety in transportation.
They even have some excellent videos and simulations showing restrained versus unrestrained children.

Very recently, UA1676 made the news when a baby flew out of a mother's arms after encountering turbulence, and landed (safely) a few rows away.

No one ever listens to Zathras. "Quite mad," they say. It is good that Zathras does not mind. He's even grown to like it. Oh, yes. -- The NTSB is Zathras in this little Babylon 5 allegory…

@voretaq7: Nah, I don't think the NTSB has grown to like being ignored...

Cranfield University in the UK has long been involved in research on child restraint systems in aircraft.
http://www.eurekalert.org/pub_releases/2000-01/CU-Cpfg-3001100.php

Roger Hardy, Director of the Cranfield Impact Centre believes, "It is
  time to get children off laps. End of story." A topic discussed at a
  recent seminar in Washington USA, which focused on 'Child Restraint
  Use in Aircraft' gave experts the chance to put across their views on
  this crucial issue.

and list a number of relevant publications
http://www.cranfieldimpactcentre.com/publications-archive

Hardy, R.N., “The Restraint of Children in Aircraft”, Proceedings of National Transportation Safety Board Child Restraint in Aircraft meeting, Washington D.C. December 1999.
Hardy, R.N., “Dual Child Occupancy of an Aircraft Seat”, CAA Paper 93013, July 1993.
Hardy, R.N., “The Restraint of Infants and Young Children in Aircraft”, CAA Paper 92020, December 1992.
Hardy, R.N., “Restraint of Infants and Young Children”, 8th Annual International Aircraft Cabin Safety Symposium, Costa Mesa, California, February 1991.
Hardy, R.N., “Infant and Child Safety Research”, European Cabin Safety Conference, Gatwick Airport, London, September 1990.

Although the FAA still allows lap children, the NTSB does not recommend it. According to the NTSB Child and Youth Transportation Safety webpage (emphasis my own):

The NTSB Child and Youth Transportation Safety Initiative will promote
  child occupant safety in all modes of transportation with a focus on
  educating parents and caregivers about ways to keep children safe when
  traveling. The NTSB will also continue to push for adoption of its
  recommendations concerning child occupant safety, such as:
Requiring separate seats and restraints for all airplane occupants, and requiring children younger than 2 to be restrained by
  an appropriate child restraint system during air travel

They also issued a safety alert on the subject, in which they advise parents to "Purchase a ticket for all children younger than 2 years and restrain them in a child restraint system certified for use on aircraft", "Ensure that infants and small children are restrained in a child restraint appropriate to their size.", and to "Ensure that all children are properly restrained during takeoff, landing, and turbulent conditions or when the seat belt sign is illuminated".
On the flip side, seat prices are expensive, and many parents may simply choose not to fly if they are forced to buy a separate seat for their infant, so airlines and the FAA do have some pressure to continue to permit the practice.

It is clear, as voretaq7 shows, that lap children are unsafe in an air accident, and would be much safer if appropriately restrained.
However, as shown in the Wikipedia article on transport safety in the US, flying is about 750 times less likely to result in a fatal accident than driving, measured per passenger kilometre. If we can hypothesize that the increased cost of an extra ticket for the child would induce more than 1 in every 750 people who fly with a lap child to drive (the same distance) instead, the policy is saving lives.
I don't know if the above is a good argument, but it is the one I have heard to justify the policy.

We would never consider putting an infant or toddler into a car without a carseat, but we don't hesitate to do exactly this when getting onto a large airplane.

Car travel is far more dangerous than airline travel, so flying through turbulence while twirling your infant over your head blind-folded is safer than driving (sans blind-fold) with your baby in a fancy car seat.
Also, I live overseas and rarely see children in car seats here (they're usually on their parent's lap on a motorbike). While this is probably more dangerous than using a car seat, the safety practices Westerners take for granted are rare and not considered in most of the rest of the world. Similarly, American school buses usually lack seat belts. There are risks many families are willing to take that may be anathema to others.

It seems to me that holding on to a 20 lbs child when subject to strong turbulence or unexpected maneuvering would be difficult.

In my experience, this is not difficult. My love for my 20-pounder is far stronger than any turbulence. I do think people should self-assess when making their flight preparations; if they cannot handle turbulence+20 lbs, then they should buy a separate ticket and bring the appropriate "carseat" for the flight.
Hope this helps!

Welcome to Av.SE! Your answer doesn’t really provide reasons why children are safe in an aircraft without a car seat, which was the question to be answered.

This answer makes some good points but doesn't have much substance.  It'd be a lot better if you could link a some statistics about flight safety, an explanantion for why American school buses don't have seat belts, some evidence about holding a 20-lb child, or examples of people booking a separate ticket and bringing a car seat made for airplanes.


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What aerodynamics forces are acting on a jet fighter during slow flight demonstration?
I have long been contemplating the forces involved in certain maneuvers in an aeroplane and some of those maneuvers begin to break down my understanding of the forces that specifically oppose gravity. Typically this is described as lift and that is how it is explained in ground school, but they did not go over other forces that can be involved keeping a plane in the air (i.e. a non-horizontal component of thrust etc.). They probably didn't go over this as it doesn't apply (significantly) to the type of planes you're one would fly right after basic ground school.
One of those maneuvers I've thought about is a "slow flight" when performed at an air show by a jet where the jet appears to be going slower than their stall speed and at a very high angle of attack. It seems that a portion, if not all of the force keeping the airplane airborne is coming not from the wings in the form of lift but rather the thrust produced by the turbine. (Example:

)

Is my understanding accurate?
Is there a good, well known reference to aerodynamics that does not gloss over the entire gamut of forces involved during a wide range of flight situations?

Ryan, pardon my English but I couldn't understand what the second question is asking. Can you clarify a bit?

@GürkanÇetin, to me it sounds perfectly clear, though off-topic, because requests for external resources are generally frowned upon at the stack exchange (but can still be answered by simply providing suitable introduction instead).

I think the question is asking for a particular kind of aerodynamics reference. But what :)

@GürkanÇetin, I think elementary kinematics would be actually quite enough.

Not sure about this video but sometimes as the plane slows down you can hear the after burner turned on. I remember in 2010 Zhuhai Airshow a Chengdu J10 did a 160km/h slow pass with the afterburner turned on half way, after that the plane were basically "standing" on its thrust.

break down my understanding of the forces that specifically oppose gravity.

There are no separate forces that oppose specific other forces. There is simply a set of forces and they all add up and the sum divided by the inertial mass of the plane equals acceleration.
Gravity always points down, so to prevent downward acceleration, the sum of the other forces must point up. But whatever force points up can do that.

Is my understanding accurate?

Mostly yes. Thrust always points forward along the engine axis, so if the engine axis points up, so does thrust.

Is there a good, well known reference to aerodynamics that does not gloss over the entire gamut of forces involved during a wide range of flight situations?

There is really just a few forces, always:

The airfoils produce force that is approximately perpendicular to them. It grows with angle of attack (angle between the airfoil and the air flow) with one peak at the at the stall angle of attack (usually 10–15°) and another at 90°.
This force is normally described as two components, lift, which is perpendicular to the air flow, and drag, that is parallel to it. That means the second maximum of lift is at 45°, because at 90° the force is parallel to the flow and thus all drag.
Form (parasite) drag. This is parallel to the flow.
Thrust. This is always approximately forward along the engine axis.
Weight. This always points down. It is actually composed of gravity, which points towards the centre of Earth, and small contribution of centrifugal force that points away from the Earth axis of rotation, but that's just nitpicking.

And then you just need to do vector addition.
So when the aircraft flies with high angle of attack, the thrust points diagonally up, cancelling some of the weight, while the force on the wing is tilted aft, cancelling the other part of weight, but also causing huge drag, so the thrust needs to be correspondingly large. That's why only fighters and aerobatic aircraft with their large thrust/weight ratios can do this kind of stunt.
For more details I would suggest See How It Flies by John S. Denker. It covers basic aerodynamics and explains reasons behind common piloting techniques. Chapter 4 discusses the forces.

Good explanation! Maybe it would be beneficial to ensure the distinction between pitch angle and angle of attack is maintained (even though a detailed definition might be overdone in the depth required so far). If of interest, another great source of good explanations of the phenomena of flight physics, with very little math required for understanding, is the „Flightwise“ series of books by Chris Carpenter.


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How to remove clogging in aircraft fuel nozzles?
I have a dual orfice fuel nozzle (Used in CFM56 Engine/ Parker make). The secondary orifice is not opening up even at the required injection pressure. It had been not used for 3 years and I assume that it is clogged. Please suggest a method to clean this.

Is that the part you are talking about? What is the context of your question... are you doing engine maintenance or using the nozzle for another purpose not related to aviation?

@mins Thanks for your response. This is exactly the nozzle which I am using. I am a graduate student and I am using this nozzle along with swirl cup to study gas turbine engine sprays. I had a total of two nozzles, and  tested another one also. Here only secondary orifice is opening , not the primary one, which is opposite to the previous case.  kerosene is used as the test fluid.  Is this because of some rusting or clogging in cartridge valve assembly ?  I am not sure how to solve this, please help.

Hoppes No. 9 is often used for cleaning aircraft fuel injection nozzles in general. This solvent is widely available for cleaning firearms. The cleaning procedure typically involves submerging the detached nozzles in the solvent for as long as necessary, typically 10-60 minutes depending on the level of fouling.
Disclaimer: I don't have any specific maintenance data on your nozzles, so you may want be wary of the applicability of the information I offer.


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Is special permission required to take off from a field within restricted airspace?
I had a question about restricted airspace that I wanted to clear up before resuming my training Sunday; you know, to maximize time in the air.
The airport I am training at is KMRH and it's surrounded by lots of restricted/military airspace/MOAs. From what I have read, restricted airspace requires permission to fly in; however we have never done that, we just call up on Unicom and state our intentions to other pilots.
If someone here could look at an online sectional of the area and get an idea of what I am saying and attempt to explain this to me it would be very helpful. If nobody can crack through my thick skull, I can always ask my CFI!

You may also want to check when the restricted spaces are in use/restricted

"Restricted Airspace" is exactly that; it comes with various restrictions that vary between areas. According to the AIM,

"Restricted areas denote the existence of unusual, often invisible, hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles. Penetration of restricted areas without authorization from the using or controlling agency may be extremely hazardous to the aircraft and its occupants."

My old CFI's example was flying through an active artillery range. The guns are required to stop while aircraft are near. They will find you and have some very strongly-worded advice for you when you land.
Like MOAs, these areas can be "hot" at certain times. The difference here would mean that you shouldn't fly into restricted airspace while it is "hot" while there is no such restriction with MOAs, though you are requested to route around them if possible.  Some areas might require additional visibility and/or altitude requirements or restrict based on the type and class of aircraft.
"Prohibited Airspace" is not allowed to be entered at any time without prior authorization of the controlling agency or explicit permission during an emergency.

This clears it up a bit. I was confusing the markings on the blue line for restricted airspace and thought it covered the entire area i was in.

Welcome! While true, this doesn't answer the question which is about taking-off without asking permission from an airfield in a restricted airspace.

A non-towered, UNICOM airfield would be treated the same as if it weren't in that airspace

The most obvious point to make here is that KMRH is not in restricted airspace: the sectional shows that it's in uncontrolled class G airspace, with class E at 700' AGL. But having said that, there is indeed a lot of special use airspace nearby:

W-122 is a warning area
R5306A and R-5306D are restricted areas
A-530 is an alert area

You can't enter the restricted areas without permission from the controlling authority, but you can enter the warning and alert areas if you want. More details of each area are on the sectional chart, the FAA's SUA site and JO 7400.8X.
Looking at the sectional, it looks to me like A-530 is a 'gap' in the restricted areas to give access to KMRH and the three private airfields nearby. R-5306 A and D are from the ground to 18,000 MSL (up to but not including FL180, to be precise) and operate continuously. If the A-530 airspace were the same then there would be no way in or out of KMRH (over land, at least) without getting permission every time. Because A-530 is sandwiched between two restricted areas, I guess there's probably a lot of military traffic around and that's why it's an alert area rather than normal class E airspace.

I was comfusing where the restricted airspace actually was. Thank you!

The important take-away here is that all SUAs on a VFR chart are list on the "tabs" (https://skyvector.com/?ll=31.75661138994275,-79.46021327138743&chart=30&zoom=4) and should be consulted regarding details of the airspace. You can also call flight service.


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Can you identify this old cockpit canopy?
I stumbled across a cockpit canopy in the woods. What type of markings should I be looking for to identify this? And where exactly should I be looking for markings to identify this piece? Here is a photo of what I found.

Hi and welcome to aviation.se. This is not a discussion board, so please reword your question and possibly include the pictures. Identifying the canopy you found is a viable question, asking if someone wants to look at them is not. See our Help Center for details...

You might want to make enquiries in your area for any local flying/gliding clubs, if they seem interested let them know the location.  (I know glider/sailplane canopies can be detached in an emergency for the pilot to parachute out, but that seems unlikely in this case!  More likely it has just been dumped.)

Just add the photos & that would make it a good question. I'd definitely nominate to re-open the question.

How do I add pictures? @curious_cat

@JaelaWood Click on edit below your post & then in the toobar you should see an Icon to click on to add images. Alternatively post them on imgur or some place online & add the link to your post.

@curious_cat How's that?

How did you stumble upon an old cockpit. I never find stuff in the woods.

Just out and about.

@JaelaWood Good job. :)

If you hadn't said its a canopy I'd have guessed its a canoe!

Not a canoe for sure! Just very dirty.

Is the rest of the plane buried below it?

Hmph...that would be a nice find! I don't know what's under it. I haven't really thought about that.

Did you find it is central Washington State?

No. Is this potentially worth anything? If so... How do I get an honest price?

It may be worth something to a collector as a decorative piece or a museum, but I believe its no longer valid for aircraft use since it was not removed and tagged properly. Technically if this was involved in an aircraft accident you should leave it where it is and report it to the FAA.

Consider donating it to the Strategic Air & Space Museum in Ashland, Nebraska.

Do we have any updates on this? Did you go back to identify it? Would you mind sharing (approx.)  where it was?

Looks like a B-47 Stratojet to me.

Image from wattflyer.com
I'm not sure about this particular model. But usually the canopy will have part number markings on it, which can be correlated to the program.
Also, see the B-47 Stratojet association's page.

Nice find! Perhaps the canopy of the prototype. From wikipedia: During early tests of the XB-47 prototype, the canopy came off at high speed, killing pilot Scott Osler.[12] The copilot safely landed the aircraft. This resulted in a canopy redesign, and the hiring of pilot Tex Johnston as chief test pilot.`

If it was that, it would be quite a find.

@jaela click the green check mark to accept this as the best answer if you want. the checkmark is found to the left of the image

According to the B-47 Association's Loss & Ejection PDF, XB-47 went down on 11 May, 1949 at the Grant County Int'l Airport (formerly Larson AFB, formerly Moses Lake AFB, as listed in the PDF), in east-central Washington. @JaelaWood, did you find it anywhere near that location? If so, it might be quite a historic find and worth letting the Air Force or a nearby museum know about it.

@FreeMan Do we know if it was this one? Although unlikely, it would be a very nice find!

@Legisey - I haven't a clue, you'd probably have to ping the OP to see if any further progress was made on finding this.

@FreeMan Yep, I left a comment on the question too. But it seems this was the only OP activity on the whole stackExchange network.

Wow, great B-47 canopy! I happen to be rebuilding a B-47E cockpit with the intention of loaning or donating it to the Cobb County, Georgia History Museum. I remember there being dozens of the 47 spare canopies at Davis Moncton Air Force Base in Arizona as late as in the late 1980s. At this point who knows how many there are sitting around. Not much need for them, they're only a handful of B-47s in museums.
  While some of the other answers that you got about it possibly being a canopy from an aircraft that lasted in flight I would strongly doubt that because it is not cracked nor does it look like there was any damage to it.
   It looks like there might be another odd piece sitting by the front of the canopy, I would just guess that someone had gotten the canopy surplus and was going to use it for a little greenhouse or something like that. Can't think of any other reason to haul around the middle of the words unless it was actually at the shelter. Who knows, stranger things have been done.  Let us know what you find out! Thanks for the great post. By the way, if no one else told you to do this, there should be a data plate on the inside of the canopy, probably near the front on the left side. This will probably tell you the type of B-47 and maybe the serial number of the aircraft. Thanks again, Mark


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Where does upward momentum come from in leading edge vortex?
I believe I am beginning to understand how a leading edge vortex creates lift. Faster air creates a lower pressure above the wing making lift.
But I am hoping to get another view of this in terms of momentum.
Does this vortex draw in air from above, pulling it downward and as a result lifting the plane up? Or is the vortex shed downward off the tail of the wing? How does this work?

Are you asking about vortex lift?

Corrected link to: How complete is our understanding of lift?

@aeroalias Yes, I am curious about vortex lift.

@jonathan Thanks for the link. That is helpful :)

Does this vortex draw in air from above, pulling it downward and as a
  result lifting the plane up?

Yes, the bound vortex in combination with translational flow accelerates air downwards.

Or is the vortex shed downward off the tail of the wing? How does this work?

A vortex has no beginning and no end. When the wing begins to move, the vortex starts out of nowhere and has four parts: The bound vortex which travels with the wing, one parallel starting vortex which stays in place and two free vortices which connect both, running from the wingtips to the point where the wingtips were when the wing started moving. To be precise, an infinite number of vortices of infinitely small strength is created, and some cover only the center of the wing while others run over most of the wingspan.

Idealized vortex structure (own work). The wing moves to the left with the speed v. The vortices are shown as discrete lines - to be precise, the bound vortices should be a sheet of infinitesimally small vortices which extend both over the chord and the span of the wing. Chordwise, they bunch together close to the leading edge, so their average streamwise position is at one quarter of the wing's chord.
And now let me give you my advice: If you do not want to operate or to write a potential flow code, do yourself a favor and forget all that. Read here why you must endure the vortex explanation of lift, and read here for a much more intuitive explanation of it all.
If by leading edge vortex you mean the swirling air coming off the leading edge of a highly swept wing, this is a result of flow separation. The inertia of the air molecules makes it impossible for them to flow around the leading edge, and they jump off the contour, leaving a volume of lower pressure behind. This pressure bends their flow path towards the wing and sucks the aircraft upwards. Since more air follows the same pattern downstream, the whole air above the wing starts to rotate while it flows downstream. This low pressure area sucks more air in from above, just like the regular low pressure region over a straight wing does.
Along and past the inner part of the wing this downward motion is prevalent and keeps the air spinning like the regular downwash from a straight wing.

Thanks for the response. I've learned a lot from your many posts :)
Do you have any pictures or links about the 4 parts of the vortex. I'm having trouble visualizing this?
Also, I still have trouble understanding why a highly swept wing is necessary for stability from vortex lift. I could imagine that on a wing with no sweep, the vortex may not rotate sideways.. And perhaps it could become bound to the wing, maybe oscillating between building up air, bursting, and building up again. Any insight on this?
Thanks again!

@AlexK, An image (and explanation) of the bound vortex in How It Flies.

@JanHudec: I find the image in How it Flies so awful that I added my own.